Carburetor



Jan. 30, 1934.

A. J. E. ROUALET CARBURETOR Filed Feb. 27, 1931 2 Sheets-Sheet 1 INVENTORvr y cj. E. ROUALET BY l ATTORNEY j ANDRE Patented Jan. 30, 1934 Andre J. E.

1,945,483 canUnE'roB Roualet, Detroit, Mleh., assignor to v Chrysler Corporation, Detroit, Mich., a corporation of Delaware Application February 27, 1931. No. 518,609

This invention relates to an improved carburetor and particularly to improved means in a carburetor for selectively conditioning it for starting and normal running operations.

In starting an internal combustion engine, itl `has been common practice to meter the fuel for the starting and normal runningA mixtures by a single metering orifice in the fuel system and to control the rate of flow of.fuel to chamber by regulating the suction therein with The suction in a carburetor builds up rapidly during the follow-through stage of starting which occurs after the initial explosions and as a result, a metering orifice, which is suitable for regulating the flow of fuel during normal running of an engine, permits an excessive flow of fuel during the follow-through stage when, as a matter of fact, a mixture having a fuel ratio lower than that required for the initial explosion is advantageous. Excessive fuel richness during the follow-through stage causes the cylinders and intake vmanifold of the engine to load up, particularly during low temperature starting and frequently starting is unsuccessful for this reason.

When the starting fuel supply isl discharged through a main fuel nozzle of the air bled type, atomization of the fuel and other advantages of air bleeding it are not obtainable, for the flow of air to the outlet of the air bleed is cut off by a choke valve.

the choke valve. This reduction in the mixing chamber decreases atomization of the starting fuel supply whether it is discharged from an air bled or from a nozzle of the non-air bleedingtype.

The main objects of the invention vide means in a carburetor for selectively conditioning it for starting and for normal running operation; to provide means of this will not disturb a predetermined normal running fuel mixture; to provide an auxiliary starting fuel system in a carburetor which is metered independently of the normal or main fuel system; to provide an auxiliary fuel system which has an independent air bleed so as to supply air to the starting fuel discharge for atomizing choke valve is closed; to provide means'for closing the normal fuel system when the carburetor is conditioned for starting by closing of its choke valve; and to provide means for alternatively rendering the normal and starting fuel systems inoperative as the carburetor is conditioned, by the choke valve, for starting and normal operation, respectively.

6 Claims. (Cl. 2151-50) predetermining the air factor of the starting fuel mixture while the fuel is metered when the choke of the carburetor is closed during starting; to provide an auxiliary air inlet of this kind which ber of the carburetor so as to proportion the air supply during starting with the fuel supplied by the `carburetor suction; and to provide air conthe mixing trolling means of this kind which is adapted to a carburetor when the choke is only partly open during the warming up stagejwhich follows starting of the engine.

Fig. 1 is a side elevation of an internal combustion engine which is equipped withmy improved carburetor.

Fig. 2 is a vertical section showing a carburetor which embodies my invention in condition for f normal operation. y

Fig. 3 is a vertical-section of the fuel nozzle of the carburetor shown in Fig. 2.

Fig. 4 is an enlarged fragmentary viewl of the choke valve of` the carburetor showing an aux- 1 iliary air inlet valve in detail.

Fig. 5 is a view similar to Fig. 2, but showing the carburetor conditioned for starting.

Fig. 6 is a fragmentary vertical section showair flow in of the invention in condition for normal operation.

Fig. i is a view similar to Fig. 6, but showing the carburetor ingcondition for stai-ting. are to prodraft` carburetor is illustrated, but substantially the same starting mixture producing apparatus may be applied to a conventional up draft carburetor without changing the main features of the invention. The carburetor illustrated in Figs. 2 to 5 inclusive, includes a .central body `portion 1 with which is integrally formed a tubular structure 2 having a direct passage which is provided at its upper end with an airy inlet 3 and it when the. at vits lower end with a. fuel mixture outlet 4. The outlet end of the tubular structure 2 has a radial flange' by which it is mounted on a neck -6 of an intake manifold 'Las shown in Fig. 1, with the outlet 4 communicating with the intake manifold. Mounted on the inlet end ofthe tubularstructure 2 is an air cleaner 8.

A shaft 9 which carries abutterfly type choke kind which is controlled by the suctionin the mixing cham- 00 regulate the air supply to the mixing chamber of An illustrative embodiment of the invention is l shown in the accompanying drawings,` in which: 7

ing a carburetor which embodies' anotherv form 35 In both forms shown in the drawings, a down valve l0 extends transversely of the ytubular structure -2 and is located in close proximity to its upper end. This yvalve is provided with an aperture 1l across which radial ribs 12 extend. The ribs 12 are integrally joined at the center of the aperture 11 by a small disc 13 having an opening 14 through which a valve stem 15 passes. Formed on the lower end of the valve stem 15 is a valve plate 16 which is normally held in a closed position and against the lower side of the choke valve by a spring 17 that bears between a collar 18 on the upper extremity of the valve stem and va washer 19 that is seated upon the upper side of the disc 13. The spring 17 yieldably holds the valve 16 in a closed position. Located at the outlet end 4 of the tubular structure 2 is abutterfly type of throttle valve 20 which is carried by a shaft 21 that extends transversely of the tubular structure 2 and which is rotatably mounted in the Wallsk thereof. The interior of the tubular structure 2 provides a mixing chamber 22 in which fuel and air are mixed together before they are fed to the intake manifold of the engine. y

'Ihe carburetor includes a fuel reservoir 23 which is formed integral with the central body portion 1 and spaced from the ltubular structure 2. Formed in the lowervend of the central body portion 1 is av well l24 which communicates through a passage 25 with the bottom of the reservoir.l A fuel passage-26 which communicates at vone end with the well 24 and at its other end with Athe interior of the mixing chamber is' also provided in the body portion of the carburetor. Located in the mixing chamber 22 is a Venturi throat 27 having an arm 28 on which is mounted. a fuel nozzle 29. `The arm and fuel nozzle 28 and 29 are provided withcommunicating passages 30 and 3l which also communicate with the fuel passage 26. vThe nozzle 29 has an air passage or bleed 32 which` extends and opens into the mixing chamber at its upper end and which is closed 'at its lower extremity. Transversely extending apertures 33 are formed in the partition 34 between the fuel passage 3l and air bleed 32 for admitting air into the fuel passage 31. This construction is typical of conventional air bled nozzles which in some cases communicate directly with the fuel passage of the body portion of the carburetor and extend into the mixing chamber at an inclination to the axis thereof, the particular construction shown being illustrative of a workable form.

The nozzle 29 and the passages by which it is connected with the well 24 form a normal fuel system for supplying fuel to the mixing chamber during normal operation of the engine. The lower end of the well 24 is closed by a threaded plug 35 having a central bore 36 and a communieatingV peripheral groove 37. The peripheral groove 37 of the plug 35 communicates with a horizontal fuel passage 38 whichleads vto a vertical fuel passage 39 extending upwardly through the central bodyv portion 1 of the carburetor. Threaded in the lowei end 'of the bodyportion 1 of the carburetor is a metering screw 40 having a metering orifice 41 located atthe junction of the passages 38 and 39. The-upper end of the vertical vpassage 39 communicates' with an annular chamber 42 through which a pipe- 43 passes. The tubularstem 43 extends through the f body portion l ofthe carburetor and has an outlet 44 communicating with themixing chamber 22. Formed on the other end of the stem is a threaded plug 45 having a restricted air I .is

inlet or bleed 46 that communicates with the atmosphere. That portion of the stem 43 which 1s located in the annular chamber 42 is provided with apertures 47 for admitting fuel from the passage 39 to the interior of the stem. The bore 36 and groove 37 of the plug 35, together with theA passages 38 and 39 and the body portion of the carburetor and the passage through the stem 43 form an auxiliary starting fuel system which is adapted to introduce fuel into the mixing chamber independently of the main or normal fuel system.

Located in the well 24 at the junction of the normal and starting fuel systems, is a fuel valve 48 which is carried by a valve stem 49 that extends upwardly through a, passage 50 in the bodyportion of the carburetor. This valve has a lower conical extremity 51 which registers with the'bore 36 of the plug 35 and an upper conical extremity 52 which is adapted to seat upon a valve seat 53 at the upper end of the well 24. The valve 48 is normally held in its lower most position shown in Fig. 2, so as to close the starting fuel system, by a spring 54 which is located in the passage 50 and which surrounds the valve stem 49. The spring 54 bears between a collar 55 on the stem 49 and a plug 56 which is threaded in the upper end of the passage 50. When the valve 48 is in its uppermost position it engages theV valve seat 53 and closes the inlet end of the normal fuel system.

The valve 48 is provided with actuating mechanism by which it is controlled so as to close the normal fuel system and open the starting fuel system ior conditioning the carburetor for normal engine operation. This manipulation of the fuel valve may be accomplished by apparatus (not shown) which is adapted to be actuated by the varying degrees of suction existing in the mixing chamber during cranking and during normal operation of the engine, respectively, or in any suitable manner, but in the forms illustrated, the fuel valve is operated in timed relation with the choke valve 10 which, in practice, is closed to condition the carburetor for starting and opened to condition it for normal operation.

Thevvalve actuating mechanism, illustrated in Fig. 5 includes a lever 57 which is pivotally mounted at 58 on a lug 59 extending outwardly from the side wall of the tubular structure 2. One end of the lever 57 has an aperture for receiving the'valve stem 49 and the other end of tion so as to hold the valve 48`off of the inner.

extremity of 'the plug 35 and retain it in engagement with the valve seat 53. This laction of the lever 57 opens the starting fuel system and closes the normal fuel system and places the'spring 54 under compression.. As the choke'valve l0 is rotated to its open position shown in Fig. 2, the cam 60 permits the lever 5.7 to be turned in a clockwise direction under the action of the 1'spring 54 which urges the valve 48 downwardly, .closing the starting fuel system and opening the normal fuel system. 'Ihe characteristics of the springs 54, 61 and 62 may be suitably predetermined so as to permit a limited relative movement between the lever 57 and valve stem 49 during the initial opening o1' the choke valve. 15(

. mixtures may be accurately predetermined independently by employing metering orifices of proper sizes. Since only one of the fuel systems 'are operable at a single time. with the exception of the period at which the change from one fuel system to the other is made, it is impossible for the fuel mixture produced by either'fucl vsystem'l to be effected by the other.

The air bleed 46 which communicates directly with the starting fuel system and with the atmosphere assures a sumcient supply of air to properly atomize the f uel which is discharged from the starting fuel system.

In carburetors for internal combustion engines of some types, Aitv may 'be found unnecessary to shut off the starting fuel system during normal operation and in this event only a valve that is adapted to render the normal fuel system inoperative during starting is requested. Under 'such conditions, a'carburetor of the form shown in Figs. 6 and 7 may be employed to advantage.

This carburetor is mainly identical inl its general construction to the carburetor shown in Figs. 1 to 5 inclusive and it includes a ycentral body portion and conmiunicating at its other end with the mixing chamber. A Venturi throat 27 having an l arm 28 that is provided -with a e '30' is located in the mixing chamber 22'. The e 30' communicates with the fuel passage 26' at one end and with a fuel nozzle 29' at its other end. The passages 26', 30 and the nozzle 29 form a normal fuel system for supplying fuel from the reservoir 23' to themixing chamber of the carburetor during normal operation of the engine.

A vertically extending -passage 65 having a metering oriiice 66 communicates at one end with the interior of the reservoir 23 and at its other end with a chamber 42' in the central body .portion 1'. Extending through the chamber 42 and central body portion 1' is a tubular stem 43' which hasan enlarged threaded end 45' that is provided with an air bleed 46'. Formed in that portion of the stem 43' which is located in the cham ber 42' are apertures 47' for admitting fuel from.

the passage 65 into the stem 43'. 'Ihe stem 48' and passage 65 form a starting fuel system which supplies fuel to the mixing chamber 22' independently of the normal fuel system.

The starting fuel system is at all times in communication with the source of fuel or reservoir and even during normal operation of the carburetor, it may operate to supply a portion of the fuel required for such normal operation. If desired, the outlet of the starting fuel system may be placed sufficiently above the fuel level of the reservoir to prevent the discharge of .fuel during normal engine operating. A valve 48' however, is provided in thewell24' to close the normalfuel system during starting so as to allowthe starting fuel system` to voperate independently, in proy 'ducing a predetermined startingv fuelmixture. 80

This valve is carried on a valve stem 49' which extends through a passage 50'` in thecentral body portion by a spring 54' that bears at one end x upon a collar 55' on the valve stem, andat the other'end upon a threaded plug 56 located in the 85 upper extremity of the passage 50.

Thefuel valve 48' is provided with actuating mechanism substantially identical to that shown in Fig- 5 which includes af-pivotally mounted lever 5'1'v having an aperture in one end through 90 which the valve stem 49', extends. The respectively opposite sides of the lever 5'1" are engaged by springs 61'. and 62' which bear-at their outer endsupon collars or nuts 63' and 64', respectively. During closing of the choke valve 10', the 95 lever 57' is rotated in a counter-clockwise direction by a cam (not shown) in Figs. 6 and '7, iden- -ticalto the cam 60 shown in Fig. 5 so as to lift' the valve 58' into engagement with the valve seat 53'-at the upper end of the wellk 24'. This action 100 closes the normal fuel system as the carburetor is conditioned for starting yby operation of the choke valve. The valve mechanism may also be manipulated by apparatus (not shown) which is operable by the changing degreeof suction existing in the carburetor and fuel system of the en- 1' with which is integrally formed a tubular gin e. l f, V With both forms of the invention, the `outlet of the starting fuel may-be extended from the carburetor and coupled into the manifold or con- `nected in communication with any of the chambers ofthe vengine which receive thefuel mixture.

The air entering the mixing chamber through the air bleed of the starting fuel system forms only a part of the quantity of air required to produce a suitable starting mixture and therefore provision is made to admit a controlled supply of air directly into the mixing chamber through the yieldable valve 16 `in one` form of the invention and 16 in the other form. This yleldable valve 120 is controlled by the suction in the mixing chamber and it may be calibrated, by predetermining the size of the opening and the tension of the spring 16, so as to accurately proportion the quantity of air drawn into the mixing chamber by the suction created during cranking of the engine with respect to the fuel that is drawn into the mixing chamber by this suction from the calibrated fuel system.-

Although but several specific embodiments of this invention have herein been shown and described, it will be understood that various changes in the size, shape and arrangement of parts may be made without departing from the spirit of my invention and it is not my intention to limit its scope other than by the terms of the appended claims.

what I claim is:

1. In an internal combustion engine having a chamber for receiving a fuel mixture, a carburetor having a mixing chamber communicating with the fuel mixture receiving chamberfofisaid engine, a choke valve in the air inlet of saidnixing chamber for conditioning the air factor of-said carburetor for starting, a normal fuel system including a passage for supplying fuel to'said mixing chamber. a starting fuel system having independent outlet communicating with theffiia'el mixture receiving chamber of said engine, a fuel valve for positively closing said passage rendering said normal fuel system inoperative, means for operating' lsaid choke valve and said fuel valve in timed relation `so as to open said fuel valve' lonly when said chokevalve is opened beyond a predetermined position, and yieldable means operable by the suction'insaid mixing chamber for controlling the direct supply of air thereto when said choke valve is closed. Y

2. vIn an interal combustion engine having a; chamberfor receiving a fuel. mixture, a carburetor having a mixing chamber 'comunicating with' the fuel mixture receiving chamberl of said` engine, a choke valve in the air inlet of said mixing chamber for conditioning the air factor of said carburetor for starting,'a normal fuel system for supplying vfuel to said mixing chamber, a

starting fuel system having `anv outlet communicating with the rfuel mixture receiving chamberA of said engine, a fuel valve for alternatively rendering said normal and starting fuel systems'inoperative, means for operating said choke valve and fuel valve in timed relation so as to open the starting fuel system and close the normal fuel system when-said choke is closed beyond a predetermined position', and to close the, starting fuel system and open the normal fuel system when said choke valve is opened beyond a predetermined position, and yieldable' means operable by the suction in said'fmixing chamber for controlling the direct supply of air thereto when said choke valvev is closed;

3. In a carburetor including a body portion having amixing chamber and having a pair of fuel passages therein, each connected with the other "fuel valve to close the fuel passage leading to said nozzle when said carburetor is conditioned for starting and to close the other fuel passage when said carburetor is conditioned'for normal operation. y l i 4. In a carburetor including a body portion portion of said carburetor having an air passage having a mixing chamber and having a pair of fuel passages therein, each connected with the other at-one end and having an outlet end opening into said mixing chamber, a fuel reservoir in said- -body portion communicating lwith the connected ends of said fuel passages, afuel nozzle in said mixing .chamber communicating with the outlet end of vone of said fuel passages, a fuel valve for closingthe latter passage, the body therein lcommunicating with the other fuel passage for atomizing thestarting fuel discharge, a

Vchoke vvalve in said mixing chamber vfor conditioning the air factor of said carburetor for starting, and means for operating said fuel valve to close the fuel passage leading to said nozzle when said carburetor isconditioned for starting.

5. A carburetor includinga mixingchamber, a choke valve in the air inlet of said chamber having an auxiliary .air inlet including a member movable to open positionby suction'when said choke valve is closed for controlling the main supply of air to said chamber during starting, a normalfuel system having la passage communicating with said mixing chamber, a starting fuel system having an outlet communicating with said mixing chamber and having' an air bleed leading directly to said outlet, a fuel valve in said passage,

and, means forsimultaneously closing said fuel and choke valves so as to vcondition said carburetor for starting.r

6. In a carburetor, a fuel reservoir, a body portion having a mixing chamber and having a pair of fuel passages therein, each communicating with said fuel reservoir and having an outlet opening into said mixing chamber, a fuel nozzle in said mixing chamber communicating with the outlet en d of` one of said fuel passages, a fuel valve for. closing the latter passage, a choke valve in the air inletl of said mixing chamber for conditioning the air factorv of said carburetor for starting,vmean s for operating said fuel valve to close the fuel passage leading to said nozzle when said carburetor isconditioned for starting, and yieldable means; movable to open position when 120 said choke valve is completely closed and operable by the suction in said mixing chamber for controlling the direct supply of air thereto when said choke valve is closed.

'ANDRE J. E. ROUALET. 

